HDR Video Transcoding with Embedded Format Conversion to SDR
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Solution Overview
Problem
When transcoding high dynamic range (HDR) videos to standard dynamic range (SDR) for devices that do not support HDR, the resulting images appear abnormal, such as being pale, due to direct encoding from HDR bitstreams to SDR formats without proper format conversion.
Innovation Solution
A transcoding apparatus deployed at the transmit end, comprising a decoder and an encoder, embeds format information into the image and performs format conversion based on preconfigured expected format information, ensuring correct transcoding and image quality at the receive end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If HDR video is directly encoded to SDR format without format conversion, then transcoding process is simple, but the resulting image quality deteriorates (image appears pale)
Solution Approach 1:
The patent applies preliminary action by embedding format information (such as transfer characteristics and color space data) into the decoded HDR image before encoding. This pre-preparation ensures that the encoder has the necessary information to perform accurate format conversion, preventing image quality deterioration while maintaining a relatively simple transcoding process.
Solution Approach 2:
The patent uses format information as an intermediary element that bridges HDR and SDR formats. By extracting format information from the HDR bitstream, embedding it into the image, and using it to guide the encoding process, the system enables accurate format conversion without requiring complex real-time analysis during encoding.
2Manufacturing precision
If format information is embedded and format conversion is performed, then image quality is maintained, but transcoding process complexity increases
Solution Approach 1:
The format information extraction and embedding steps are performed as preliminary actions during the decoding phase, preparing the image data in advance for encoding. This approach maintains image quality while organizing the complexity into manageable, sequential steps rather than complex simultaneous operations.
Solution Approach 2:
The system uses self-service by automatically extracting format information from the HDR bitstream and embedding it into the image without requiring manual intervention or complex external processing. The transcoding apparatus performs these operations autonomously, reducing the burden on external systems while maintaining image quality.
3Adaptability or versatility
If HDR format information is not preserved during transcoding, then device compatibility is improved, but information accuracy is lost
Solution Approach 1:
The patent uses embedded format information as an intermediary that carries HDR characteristics through the transcoding process. This information acts as a guide for the encoder, allowing the system to produce SDR output compatible with various devices while preserving the original HDR format characteristics for accurate conversion.
Solution Approach 2:
The system implements feedback by using the embedded format information to guide the encoding process. The encoder references the embedded format information to make informed decisions about format conversion, ensuring that the transformation from HDR to SDR accurately reflects the original image characteristics while maintaining device compatibility.
Data Source
AI summary
A transcoding apparatus including a decoder and an encoder is disclosed. The decoder is configured to: receive a first bitstream output by an application; decode the first bitstream to obtain a first image and first format information of the first image; embed the first format information into the first image to obtain a second image; and send the second image to the application. The encoder is configured to: receive a third image output by the application, where the third image is the second image or an edited version of the second image that is modified by the application; determine second format information based on the third image; obtain preconfigured third format information; perform format conversion on the third image based on the second format information and the third format information to obtain a fourth image; encode the fourth image to obtain a second bitstream; and send the second bitstream to the application.